In the area of the quality control of vehicle bodywork, there is the need, before the painting operation for example, to verify that the doors are correctly positioned relative to their frame. The purpose of this inspection is to determine whether the value of the clearance vis-à-vis the frame around the entire periphery of the door lies within a range of tolerance. Also said inspection must determine whether or not the door lies flush with the frame. Any misalignment of the door must also be inspected at various peripheral points of the door.
The difficulty with this operation to inspect the clearance and/or misalignment of a door lies in the fact that this inspection is carried out when the latching system of the door is still not mounted. Yet, measurement of clearance and/or misalignment can only be meaningful if the door occupies its reference closed position as determined by the engaging of the strike plate of the latch system into its housing.
To ensure the inspection of vehicle doors on a production line, it is known from document JP 2003 25 47 43 for example to place magnets at strike plate level at the entry to the inspection station so as to position the door in its reference closed position. In this position of the door, measurements of clearance and/or misalignment are made using a system of measurement sensors performing measurements at different inspection points distributed around the periphery of the door, so as to determine whether or not the door occupies a correct position relative to the frame. On leaving the inspection station, the magnets are removed from the vehicles.
So as to automate the positioning of doors in their reference closed position, it is known to equip the inspection station with a mechanical system for reference positioning of the doors. The mechanical system comprises an automated arm which carries a beam provided with suction pads, the beam intended to come into contact with the door and the frame so that the door takes up its closed reference position. The forced positioning of the door with said mechanical system gives good results in terms of reliability. However, this mechanical system has the disadvantage of requiring a particular embodiment for each vehicle profile. Additionally, the design and maintenance costs of said mechanical device are very substantial.